1. Field of the Invention
The present invention relates to apparatus for pulling stakes used in agriculture, and more particularly for removing stakes and strings used in growing tomatoes and the like over plastic mulch covered beds.
2. Description of the Prior Art
A variety of produce is grown in the field utilizing rows of wood stakes which may support strings or lines upon which the plants can grow. Tomato crops are typical of produce grown in this fashion. Where tomatoes are to be mechanically harvested, stakes are generally not necessary; however, where picking of tomatoes by hand is desired, stakes and strings are necessary to keep the vines off the ground to provide ready access to the fruit during picking. An important instance where stakes are required is the growing of tomatoes over plastic mulch covered beds. Over the past fifteen years, the technique of growing tomatoes and other plants on plastic mulch covered beds has been developed. Although the method is particularly effective for use in sandy soil, it is proven to have many other advantages: cleanliness of the fruit; good control of weeds; improved action of soil fumigants; reduction of root rot; reduction of soil moisture evaporation; prevention of soil erosion; and protection against freeze damage. The plastic mulch method is becoming more widely used; for example, during the 1976-77 season in Florida, over 75% of the 35,000 acres of fresh market tomatoes produced in that state were grown in plastic mulch covered beds. Planting is through holes punched or burned in the plastic film. It is also common to include drip irrigation tubing along the bed underneath the plastic mulch for watering and fertilizing of the bed. This system for growing tomatoes has proven to be more energy efficient per unit of product than the traditional system of growing the plants on bare ground, thus, the technique may be expected to become more widespread throughout the United States.
Available mechanical harvesters have proved unsatisfactory for operation over plastic mulch beds. The plastic film becomes torn and shredded, causing clogging of conveyor belts, separators and other moving parts of the machinery, and the irrigation tubing is usually damaged. For this reason, tomatoes and other produce grown on plastic mulch must be harvested manually. Therefore, wood stakes and plastic monofilament lines are required for ease of hand picking when tomatoes and similar plants are grown over plastic mulch covered beds. After harvesting of the crop and prior to planting of the next crop, it is necessary to remove the stakes and the lines. The removed stakes are collected and stored for reuse for crops. It is present practice to utilize hand labor to pull each stake, transport the stakes to a collection point along a row, and to have trucks later drive through the fields collecting the stakes and returning them to the storage point. As may be recognized, the cost of such hand labor, and the time involved is significant. For example, in Florida the total cost of removing stakes from a typical field is about $50 per acre. Additionally, such field workers tend to be careless, and breakage and loss of stakes is quite common. As may be recognized, the bill for stake removal of stakes from the plastic mulch grown tomatoes in Florida for only one crop will approach two million dollars. This cost is, of course, passed along to the consumer in the cost of the produce.
No positive or effective machines are known that can mechanically remove the lines and pull and collect the stakes from agricultural fields. Thus, such apparatus is needed to reduce this phase of cost of raising agricultural crops.